The first trailer for Brad Pitt‘s highly-anticipated film World War Z, was released Thursday.

In the film, based on Max Brooks‘ best-seller World War Z: An Oral History of the Zombie War, Pitt plays Gerald Lane – a United Nations researcher roped in to help find the origins of the plague that has turned hundreds of millions of people into zombies.

The trailer begins with an endearing family scene; Brad Pitt and Mireille Enos (who play the couple Gerry and Karen Lane) are in the car with the children, when all traffic suddenly comes to a standstill and the scene rapidly turns into one of horror. And zombies. There are, in fact, a LOT of zombies in this trailer. Like, a LOT of them. Piles and piles of zombies, cascading down a flight of stairs, more piles of zombies, storming around, trying to pile on top of each other and scale a wall. More piles of zombies, writhing around and looking like the most expensive pile of zombies in movie history.

World War Z is the first in what is hoped will be a multi-film franchise, but it has faced a bumpy start.

The project – said to cost $180-million – began filming in 2011 with an eye towards a release this holiday season. According to Entertainment Weekly, disagreements grew between director Marc Forster (Finding Neverland) and producer-star Pitt. Earlier this year, the movie’s already-filmed third act was canned and rewritten completely by Prometheus wordsmith Damon Lindelof, and a new ending was created.

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